The present invention relates to a process of tire manufacture and assembly drums serving to practice the process.
The invention relates more specifically to the manufacture of tires comprising a casing carcass and at least one reinforcing bead wire in each of the beads, around which the casing carcass is rolled forming a fold such that, contrary to common practice, the fold of the casing carcass is arranged between the bead wire and the casing carcass itself.
Some manufacturing processes employ assembly drums comprising shoulders, in particular, against which the wire is brought by describing an axial movement. The wire is held against the shoulder by simple adhesion between the materials or by an additional means. Such drums may employ bead wires directly, or separately fabricated semifinished products consisting of the bead wire surmounted radially by a section of rubber composition. Hereinafter, the term “bead wire complex” will be used to mean a bead wire alone, a bead wire surmounted by a section of rubber composition, optionally further comprising a coating compound for the bead wire filler such as another rubber composition section or a rubber ply comprising cords.
By way of example, mention may be made of publication FR 1,397,751, describing such an assembly drum with shoulders having a single working position, nonexpanding, for rolling the casing, and a (radially) retracted position for axially extracting the tire casing produced. The bead wire complexes are laid on each shoulder during fabrication of the casings respectively and held in place by an axially displaceable accessory means.
Such drums serve for tire fabrication by process steps consisting of:                Positioning the casing carcass on the drum with its ends axially passing beyond the surface of the drum,        Applying said ends against the shoulders of the drum, generally with the aid of axially displaced depressing fingers,        The positioning the bead complexes against the shoulders of the drum,        Finally, actuation of folding means generally consisting of inflatable envelopes to lift the ends of the casing carcass and thus fold the carcass around said complexes without changing their positioning.        
Thus it is not possible, with such drums, to arrange the fold of the casing carcass between the bead and the carcass itself. Actually, this method cannot fold the ends of the casing carcass under the bead complexes when the latter are already in position against the casing.
The object of the invention, then, is to manufacture a tire by using bead wire complexes in which the casing carcass fold is positioned between the bead wire and the said casing carcass.